Oo normal talaga, lalo na sa 5 months, hiccups are super common sa babies at walang harmful, it's just their nervous system developing pa lang! A few of my mum friends were worried din nang malalim when their babies were that age, pero docs assured us na kahit gaano ka-frequent, di sila uncomfortable or anything to stress about. Try lang mo i-burp siya after feeding or change his position, pero honestly pag sobrang anxious ka, better to ask your pedia during checkup para sa peace of mind mo. You're doing great na nag-observe ka, first time mom jitters talaga yan!